Spark-plug.



M'. G. BUNNELL.

SPARK PLUG. APPLICATION man FEB. 11. 1916.

Patented J1me 12, 1917.

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UNITED STATES PATENT OFFICE.

MORTON Gr. BUNNELL, OF CHICAGO, ILLINOIS, ASSIGNOR TO GEORGE C. MASTIN, OF CHICAGO, ILLINOIS, AND EDWARD W. STEES, OF ROCKFORD, ILLINOIS; MABEL C. FUTNAM EXECUTRIX OF SAID GEORGE C. MASTIN, DECEASED.

SPARK-PLUG.

Specification of Letters Patent.

Patented June 12, 1917.

Application filed. February 11, 1916. Serial No. 77,573.

To all whom it may concern:

Be it known that I, MORTON Gr. BUNNELL, a citizen of the United States of America, and resident of Chicago, Cook county, Illinois, have invented a certain new and useful Improvement in Spark-Plugs, of which the following is a specification.

My invention relates to spark plugs for internal combustion engines.

Generally stated, the object of my invention is to provide a spark plug having a novel and efiicient means for holding the plug portion in the socketpiece, so that the plug of insulation can be locked in place and removed at will, without the necessity of using tools, whereby the general construction is rendered stronger and less liable to break than heretofore, as will hereinafter more fully appear.

To these and other useful ends, my invention consists in matters hereinafter set forth and claimed.

In the accompanying drawings 2-- Figure 1 is a side elevation of a spark plug embodying the principles of my invention, showing the plug of insulation locked within the socket-piece which screws into the cylinder.

Fig. 2 is a similar view showing the plug removed from socket-piece.

Fig. 3 is a verticcal section on line 33 in Fig. 1.

Fig. A is another side elevation of the plug as shown in Fig. 1, showing a different side thereof.

Fig. 5 is a side elevation of the socket piece.

As thus illustrated, my invention comprises a plug of insulation A which is formed to enter and be seated in the metal socket-piece B, which latter is provided with a threaded portion 7) which screws into the cylinder of the engine. This socket-piece is provided internally with upper and lower seats 1 and 2, and with external and laterally projecting lugs 3, which latter are disposed in the plane of the longitudinal axis of the plug. A steel bail C is pivoted at 4; to the sides of the metal jacket D which incloses the upper portion of the plug of insulation A, the lower end of this jacket bearing against the seat 1, as well as against the shoulder a on the insulator, and a washer 5, r a plurali y o a e b ing i t r "of these slots engage the under sides of the posed between said sleeve and said seat to make a tight joint. The shoulder 6 on the plug A bears against the seat 2, one or more washers being interposed between this shoulder and seat to form a tight joint. It will be understood that these washers 5, and also the washer 7 below, can be of any suitable material, such as copper, or other compara tively soft metal, so that some slight yielding action will take place when the plug is forced into the socket-piece. The said bail C has its lower end portions enlarged and provided with cam slots 0 which are curved concentrically to the axis afforded by the pivots i, whereby the lower edges lugs 3 and serve as cams to force the plug A downward into the socket-piece when the upper end or handle portion of the said bail is swung to the right from the position thereof shown in Fig. 2, and into the position shown in Fig. 1, thus firmly locking the plug of insulation within the socketpiece. The pivots 4c are, it will be seen, a little to the left of a vertical plane extending through the center of the lugs 3, so that the said. pivots and lugs are out of alinement, the result being that when the parts are in the position shown in Fig. 1, the internal pressure of. the engine cylinder against the inner end of the plug A tends to produce a tightening action of the said cam mechanism, inasmuch as this pressure on the plug and the resulting increased pressure of the lugs 3 against the edges 8 tend to move the bail slightly from time to time in a direction which will ultimately bring the ends of the cam slots 0 against the said lugs-that is to say, the tendency is to tighten the plug in the socket-piece as the result of the explosions in the engine cylinder.

The upper edges 9 of the said cam slots bear upon, the tops of the lugs 3, and when the bail C is swung to the left from the position shown in Fig. 1, and into the position indicated in Fig. 2, the result is that the plug A is forced slightly upward, these edges 9 acting as cams to slightly raise the plug A in the socket-piece. As soon as the lugs 3 have been disengaged from the open ends of the cam slots 0, the plug A is then ready, without any rotation thereof, to be.

lifted out of the socket-piece.

45 jacket.

Thus, the bail serves to forcibly withdraw the plug A a distance from the socketpiece B, as well as to force the plug within the socket-piece, and this is all accomplished 5 without the necessity of rotating the lug in the socket-piece. Owing to the 0 -center arrangement of the pivots 4, the pressure on the inner end of the plug has a tendency to move the bail C in the direction which is used to tighten the plug in the socket-piece,

and not in the direction which is employed to release the plug from the socket-piece. It follows, therefore, that the successive impacts of the explosions within the cylinder,

against the inner end of the plug A, will not be liable to loosen the plug in the socketpiece, or to gradually jar the bail G into the position shown in Fig. 2, but, to the contrary, will have a tendency to keep the bail in the position shown in Fig. 1 and, in some measure, to gradually move the bail a little farther in this direction, thereby tightening the locking mechanism instead of loosening it, in a manner that will be readily understood.

The lower end of the plug A is provided with metal terminals E of any suitable character, which are in contact with the socketpiece B, and which are thus included in the electric ignition circuit in the usual and well-known manner. The center terminal F extends upward within the insulation at the lower end of theplug A and is connected with the metal conductor f which projects upwardly a distance above the top of the plug. A washer of insulation G is seated upon the top of the plug A, being of a size to overlap the metal jacket D, and the usual binding post H is provided at the top for holding a circuit wire.

be removed from the outer end of the insulator. When all the parts are fully assembled, the insulator A is completely inclosed by the socket-member B and the metal jacket D, in the manner shown in Fig. 3, so

that no part of the insulator is exposed.

Thus constructed, the spark plug has only one axis, which'is the axis about which the bail C is movable from one side of the plug to the other, and the construction is such, as previously stated, that when the bail is in looking position, as shown in Fig. 1, the reaction between the socket-member B and the jacket I) is communicated to the hubportions of the bail in such a manner that 6' the handle-portion of the bail has a tendency to move fm'ward-that is to say, in this condition there is no force tending to rotate the bail in a backward direction, and consequently the impacts and jarring of the engine will never cause the bail to grad ually work around into the position shown in Fig. 2, which would release the insulator and jacket from the socket-member. Under the conditions of actual. use, the bail C is self-retaining in the position shown in Fi 1, as in this position it has a constant tendency to rotate forward instead of backward, but it is not adapted or intended to be selfretaining in any other position.

lVhat I claim, as my invention .is:-

1. A spark plug comprising a metal socket-member adapted to be attached to the cylinder of an internal-coinlnistion-engine, an insulator adapted to enter said socketmember, a metal jacket inclosing the outer portion of said insulator and adapted to enter the socket-member, a bail provided with hub-portions, means to pivot said hub-portions upon the opposite sides of said jacket, lateral projections on the socket menlber, means carried by said hub-portions to engage said projections and thereby hold said insulator and jacket tightly within the socket-member when said bail is moved in one direction, and means on said hub-portions to engage said projections and thereby partially withdraw said insulator and jacket from the socket-member when said bail is moved in the opposite direction.

2. The spark plug (substantially as set forth in claim 1), said bail being arranged to swing from one side of the plug to the other to connect or disconnect said jacket and socket-member, and said engaging means on the hub-portions of the bail consisting of the opposite'je .s of an eccentrically curved slot.

3. The spark plug (substantially as set forth in claim 1), the axis of said bail being at right angles to the length of said insulator and disposed out of line with said projections longitudinally of said insulator.

4. The spark plug (substantially as set forth in claim 1), said jacket being removable from the outer end of said insulator, and retaining means on the outer end of said. insulator to engage the end of said jacket, said SOOkGll-DIGHllOGl' and jacket ontirely inclosing said insulator.

5. The spark plug (substantially as set forth in claim 1), said socket-member having a plurality of shoulders forming seats therein, said insulator having a shoulder for engaging one of said seats, the inner end of said jacket engaging another of said seats, and said insulator having a shoulder for engaging the inner end of said jacket.

6. A spark plug comprising a socket-member adapted to be connected with the cyllnder of an internal-combustion-engine, said member having a plurality of shoulders forming annular seats therein, an insulator provided with a shoulder for engaging one of said seats, a metal jacket inclosing the outer portion of said insulator and provided with means for engaging another of said seats, said insulator having a shoulder for engaging the end of said jacket, adjustable means on the outer end of said insulator to engage the outer end of said jacket and thereby draw said insulator firmly against the inner end of said jacket, so that said jacket is removable from the outer end of said insulator,- and means operable without rotation of said jacket and insulator to removably hold said jacket firmly seated in said socket-member.

7. A spark plug comprising a socketmember adapted to be connected with the cylinder of an internal-combustion-engine, an insulator in said socket-member, a metal jacket inclosing the outer portion of said insulator and extending into said socketmember, means on the insulator for engaging the inner and outer ends of said jacket and whereby said insulator is removable from the inner end of said acket and cannot be removed from the outer end thereof, and means operable without rotation of said jacket and insulator for readily connecting and disconnecting said jacket and socketmember.

8 The spark plug (substantially as set forth in claim 1), and means on the outer and of said insulator to engage the outer end of said jacket and thereby cause out ward movement of said insulator when said bail is moved in said opposite direction.

9. A spark plug comprising a metal socket-member adapted to be attached to the cylinder of an internal-combustionengine,

an insulator adapted to enter said socketmember, a metal jacket inclosing the outer portion of said insulator and adapted to enter the socket-member, a bail provided with hub-portions, means to pivot said hubportions upon the opposite sides of said jacket, lateral projections on the s0cketmember, means carried by said hub-portions to engage said projections and thereby hold said insulator and jacket tightly within the socket-member when said bail is moved in one direction, and means on the insulator to engage the opposite ends of the jacket, so that said jacket forms a bottomless receptacle for said insulator, and whereby said bail forms a swinging handle for said receptacle.

10. A spark plug comprising a metal socket-member adapted to be attached to the cylinder of an internal-combustion-engine, an insulator adapted to enter said socketmember, a metal jacket inclosing the outer portion of said insulator and adapted to enter the socket-member, a bail provided with hub-portions, means to pivot said hubportions upon the opposite sides of said jacket, lateral projections on the socketmember, means carried by said hub-portions to engage said projections and thereby hold said insulator and jacket tightly within the socket-member when said bail is moved in one direction, and means to removably secure said jacket on said insulator, said bail having a lever handle for the operation thereof and by which to lift said jacket and insulator out of the socketmember.

11. A spark plug comprising a metal socket-member adapted to be attached to the cylinder of an internal-combustion-engine, an insulator adapted to enter said socketmember, a metal jacket inclosing the outer portion of said insulator and adapted to enter the socket-member, a bail provided with hub-portions, means to pivot said hubportions upon the opposite sides of said jacket, lateral projections on the socketmember, means carried by said hub-portions to engage said projections and thereby hold said insulator and jacket tightly within the socketmember when said bail is moved in one direction, and means to secure said jacket on said insulator, so that said jacket is rendered removable from the socket-member by a single movement of said bail.

Signed by me at Chicago, Illinois, this 24th day of January, 1916.

- MORTON Gr. BUNNELL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, I). G. 

